Holder for fluorescent tubes



y 1954 E. GASSER-STEINER HOLDER FOR FLUORESCENT TUBES Filed Dec. 28, 1950 INVEN TOR. Enu t 6,4:562 J ram 5 R Patented July 6, 1954 UNITED STATES PATENT OFFICE 2,683,257 HOLDER FOR FLUORESCENT TUBES Ernst Gasser-Steiner, Graz, Austria Application December 28, 1950, Serial No..203,188

Claims priority, application Austria January 9, 1950 2 Claims.

This invention relates to a holder for fluorescent tubes, which holder comprises a holder body made from metal or electrically insulating material, a contact carrier for the electrical contacts, which contact carrier is also made from insulating material and firmly fitted in the holder, and a resilient sealing ring which by means of a cap nut, screwable onto the holder body, can be pressed onto the front end portion of the holder as well as on the holder-end portion of the fluorescent tube. In the known type of holder this sealing ring encloses only the tube holder, not the tube itself. At best it seals the holder space at the end facing the tube, that is, at one end only, whereas moisture and gases are still permitted to enter the holder space from the entrance end of the connecting cable. For this reason these known fluorescent tube holders cannot be used in moist spaces, nor under water or in rooms filled with explosive gases. Moreover, the holder bodies require that the ends of the fluorescent tube be fitted deeply into the interior of the holder so that the tube can be fitted and removed only in an axial direction. As a consequence, the holder must be removed too when a fluorescent tube is to be exchanged.

It is the object of this invention to essentially simplify these holders for fluorescent tubes, in construction and as regards the operation of fitting the tubes, and, moreover, to achieve a reliably gasand water-tight connection of the tube and seal of the holder.

According to a feature of the invention, only a portion of the annular contact carrier is inserted in a recess of the holding element of the socket and the cylindrical elastic sealing ring surrounded by a tightening cap attached to the holding element snugly embraces the projecting portion of said contact carrier; said cylindrical scaling ring abutting at one of its end surfaces against the holding element is of greater axial length than the projecting portion of the contact carrier whereby a projecting portion of said cylindrical sealing ring is formed for snug engagement with the end of a fluorescent tube.

According to another feature of the invention the inner end surface of the tightening cap is provided with a bevelled surface for engagement with an end surface of the sealing ring, whereby the pressure exerted by the tightening cap on the sealing ring is primarily directed to the circumferences of the contact carrier and of the fluorescent tube.

These features of the invention enable for the first time a most effective gasand water-tight 2 seal of the tube connection and of the contacts of the holder body, which seal, on the other hand, can be loosened easily and simply so as to ensure a simple fitting and removal of the fluorescent tube.

In the accompanying drawings an embodiment of the holder according to the invention is shown by way of example in Figs. 1 and 2 in a front view and vertical sectional view, respectively, whereas Figs. 3 and 4 are perspective views showing the contact carrier and its cover disk.

lhe contact carrier I, made from insulating material, has the shape of a cylindrical box and carries the known guides 2 and contact strips 5 for the electrode studs of the fluorescent tube. The bottom of the contact carrier I is tightly closed and carries the terminals 4 for the connecting leads (not shown). The bottom has two openings 5, through which the two connecting leads are passed, and countersunk seats for the fixing screws 6. This contact carrier I finds its seat in a holder body 1, of insulating material, into which holder the contact carrier is fitted only by part of its total height. The holder body 'I has an annular flange 8, which has at its periphery a thread for a cap nut I3. The holder body I is hollow and is provided behind the seat for the contact carrier I with two longitudinal ribs 9. These longitudinal ribs are provided with threaded bores, into which the fixin screws 6 for the contact carrier I may be screwed. The holder body I has a projection I I, which fits into a recess Ill provided in the cylindrical shell of the contact carrier so as to permit of the fitting of the contact carrier I on its seat only in one position, which is the correct one. The contact carrier I protrudes with a portion of its cylindrical shell out of the annular flange 8 of the holder body I so that a recess I8, provided in said shell for receiving the contact studs of the fluorescent tube, is exposed. It is possible, therefore, to fit the fluorescent tube radially of the holder axis between the holder bodies into its contact position.

The contact carrier and the fluorescent tube have equal diameters. Two sealing rings I2, the diameter of which corresponds to that of the fluorescent tube, and cap nuts 53, are passed on the fluorescent tube before the latter is fitted. After the fluorescent tube has been fitted, each of the two sealing rings I2 is axially moved thereon to such an extent that the ring encloses also the periphery of the contact carrier I. Subsequently the cap nut I3 is screwed onto the thread of the annular flange 3, whereby pressure is exercised on the sealing ring l2. Owing to the conical shape of the internal wall surface 20 of the cap nut l3, the screw pressure exercised by the nut is utilized primarily for safely sealing the tube periphery and the contact carrier. Hence, the sealing ring when compressed encloses both the contact carrier l and the glass shell of the fluorescent tube, indicated by dash-and-dot lines in Fig. 2, said glass shell having the same diameter as the contact carrier. This seal is tight enough to prevent the access of moisture, and of any gases which may be present, into the holder. The holder body I has a bracket for the electric connecting lead (not shown) and for fixing the holder. This bracket extends radially of the holder axis and has a duct I4, the end of which can also be sealed tightly by a stufiing-box [5. The stufiing-box l5 also serves for locating the holder body I at a lamp fixture or a reflecting screen. When compressed, the sealing ring H of the stufiing-box i5 encloses the connecting cable so tightly that the access of moisture or of easily inflammable gases into the contact carrier is prevented also from the entrance end of the connecting lead. Thereby it is achieved that the connection of the fluorescent tube to the electric connecting lead is actually moisture-tight and explosionproof.

At its front end the contact carrier is covered by a cover disk 11, which has guide slots IQ for the contact studs of the fluorescent tube. Said slots begin at the recess i8 provided in the shell of the contact carrier.

What I claim is:

1. A gas proof socket for receiving a fluorescent tube, said socket comprising: a holding element, an annular contact carrier mounted at one end of said holding element, a portion of said contact carrier projecting from said holding element, a cylindrical elastic sealing ring snugly embracing said projecting portion of the contact carrier and being arranged for abutting engagement with said holding element at one of its end surfaces, the axial length of said cylindrical sealing ring being larger than the axial length of said portion of the contact carrier projecting from said holding element whereby a projecting portion of said cylindrical sealing ring is formed for a snug engagement with an end of a fluorescent tube, a tightening cap embracing said sealing ring, the inner end wall of said tightening cap engaging the other end surface of said cylindrical sealing ring, and cooperating means provided on said tightening cap and on said holding element for tightly fastening said cap on said holding element.

2. In a gas proof socket for receiving a fluorescent tube as claimed in claim 1, said inner end wall of said tightening cap including a bevelled surface, and said bevelled surface being in engagement with said other end surface of said cylindrical sealing ring.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 771,259 Martin Oct. 4, 1904 1,878,229 Beck Sept. 20, 1932 2,242,273 Taylerson May 20, 1941 2,285,175 Sparling June 2, 1942 2,295,833 Williams Sept. 15, 1942 2,588,887 Semeyn Mar. 11, 1952 FOREIGN PATENTS Number Country Date 549,743 Great Britain Dec. 4, 1942 

